By Mark A. Grace
Marine fisheries research often requires considerable expertise and financial resources coupled with the pressing need to address important ecological issues, so it is essential that the research objectives provide meaningful results. However, a persistent enigma related to accomplishing some marine fisheries research objectives is the ecosystem habitats and fauna that are the objects of research can be negatively impacted by scientific survey methods. One of the most pronounced examples of this enigma is the U.S. National Oceanic and Atmospheric Administration/National Marine Fisheries Service (NOAA/NMFS) biannual bottom trawl surveys in the U.S. Gulf of Mexico (https://www.gsmfc.org/seamap-gomrs.php), particularly along the west Florida continental shelf.
In order to provide management-important fisheries data, NOAA/NMFS deploys bottom trawls along the Gulf of Mexico continental shelf from offshore of Brownville, Texas to west of central Florida. Bottom trawls contact the sea bottom during 30 minutes of trawling and captured fauna are then scientifically assessed and sampled. Because the NOAA/NMFS bottom trawls are designed to fish directly on the sea bottom, live sea bottom habitats and the associated fauna can be irreparably damaged or killed. As an example, there are NOAA/NMFS records of survey bottom trawls that could not be hauled aboard due to the weight and volume of the trawl-captured corals and sponges, or the entire bottom trawl gear was lost on sea bottom habitats or other bottom features where they remain as “ghost fishing” nets. Considering the survey trawl webbing is primarily non-biodegradable synthetic it is reasonable to expect lost survey trawls to persist for decades.
While NOAA/NMFS conduct surveys under bottom trawl damage mitigation guidelines, those guidelines are not routinely followed at all bottom trawl locations or they are not effective for all trawling scenarios (NOAA Technical Memorandum, NMFS-SEFSC-723, doi:10.7289/V5/TM-SEFSC-723). Since the NOAA/NMFS bottom trawling survey area was expanded in 2008 to include the west Florida continental shelf, there are more than 130 survey bottom trawl tows where survey trawl gear was hung, lost, or damaged due to encountering bottom habitats or other bottom features. Even though over 100 km2 of sea bottom has been swept by NOAA/NMFS survey trawls there is no scientific research supporting that when there is associated habitat damage it does not impact the Gulf of Mexico live sea bottom ecosystems. However, it is scientifically documented that live sea bottom habitats are sensitive to numerous anthropogenic stresses and when those ecosystems are damaged the effects can be ecologically catastrophic and long term.
NOAA/NMFS has the proven expertise to provide management-important fisheries data by expanding or better utilizing surveys that do not adversely affect live sea bottom habitats (surveys that record footage at reef locations, ichthyoplankton surveys, longline surveys, midwater trawl surveys). The results from those surveys have provided important NOAA/NMFS fisheries management data that have broad utility. In addition, NOAA/NMFS supports live sea bottom habitat protections (https://spo.nmfs.noaa.gov/sites/default/files/TMSPO208.pdf, and https://www.fisheries.noaa.gov/national/habitat-conservation/essential-fish-habitat). Those important NOAA/NMFS habitat protection and conservation concepts exemplify the need to safeguard fragile live sea bottom habitats from the negative effects of marine fisheries research objectives.
The statements, findings, views, conclusions, and recommendations contained in this document are those of the author, and do not necessarily reflect the views of the U.S. Department of Commerce (NOAA/NMFS), and should not be interpreted as representing the opinions or policies of the U.S. government.
About The Author
Mark A. Grace began his career with NOAA/NMFS/Southeast Fisheries Science Center in 1980 and is currently a sea-going Research Fisheries Biologist. He has participated in over 150 NOAA/NMFS at-sea research surveys or projects (35 surveys as the Lead Scientist) that span nearly 8 years of cumulative sea days. His numerous scientific publications include a recent new shark species discovery and description for the American Pocket Shark (Mollisquama mississippiensis).
This piece was prepared online by Panuruji Kenta, Publisher, SEVENSEAS Media